1. Field of the Invention
The present invention relates to a battery module.
2. Discussion of the Background
A conventional battery assembly (battery module) which includes a plurality of square-shaped unit batteries (cells) parallelly arranged in a row, partition walls that maintain the unit batteries at constant intervals, end plates that are closely attached to the outer surfaces of outermost unit batteries, and a connecting rod that connects these components in an integrated manner is well known (see Japanese Unexamined Patent Application Publication No. 2006-310309).
Such a battery assembly (battery module) typically has explosion-proof valves for closing valve orifices respectively provided in the unit batteries (cells). As the inner pressure of the cells increases due to the gasification of an electrolyte, the explosion-proof valves are configured to open to relieve the increased inner pressure.